Mobile marine drilling foundation



Sept. 24, 1963 e. A. M CAMMON 3,104,531

MOBILE MARINE DRILLING FOUNDATION Filed Aug. 25, 1959 7 Sheets-Sheet 1Fig. l

George A. McCommon Inventor Patent Attorney P 24,1963 I e. A. MOCAMMON3,104,531

MOBILE MARINE DRILLING FOUNDATION Filed Aug. 25, 1959 '7 Sheets-Sheet 2I8 I9 /3 Mk I e\ A: s\

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George A. McCummon Inventor Patent Attorney Sept. 24, 1963 G. A.MGCAMMON 3,104,531 I MOBILE MARINE DRILLING FOUNDATION Filed Aug. 25,1959 7 Sheets-Sheet 3 George A. McCammon lnvemor PotentAflorney Sept.24, 1963 e. M CAMMON 3,104,531

MOBILE MARINE DRILLING FOUNDATION Filed Aug. 25, 1959 7 Sheets-Sheet 4George A. McCammon Inventor Porem Attorney Sept. 24, 1963 ca. A.MOCAMMON 3,

MOBILE MARINE DRILLING FOUNDATION Filed Aug. 25, 1959 7 Sheets-Sheet 5George A. McCclmmon lnven'ror WWW Patent Attorney Fig. 8

p 1963 G. A. MCCAMMON 3,104,531

MOBILE MARINE DRILLING FOUNDATION Filed Aug. 25, 1959 7 Sheets-Sheet 6I: r .2 LL.

0 A IO 1 George A. McCummon Inventor Patent Attorney Sept. 24, 1963 e.A. M CAMMON 3,104,531

MOBILE MARINE DRILLING FOUNDATION Filed Aug. 25, 1959 7 Sheets-Sheet 7Fig. l0

George A. McCummon lnvemor Patent Attorney United States Patent3,104,531 MOBILE MARINE DRELING FOUNDATIGN George A. McCammon, Caracas,Venezuela, assiguor to Jersey Production Research Company, a corporationof Delaware Filed Aug. 25, 1959, Ser. No. 835,945 2 Claims. (Cl. 6146.5)

The present invention relates to an improved movable marine foundation.The invention is concerned with an apparatus for drilling oil wells inmarine. locations and submerged lands which will provide a firm, stablebase for the drilling operations and which can be readily transported byfloating from one marine location to another. The invention isespecially concerned with an apparatus and method for drilling oil wellsin marine locations and submerged lands wherein the drilling rigincluding the substructure, the derrick, the draw-works and auxiliaryequipment may be readily transported from one marine location to anothermarine location.

It is well known in the art to position drilling rigs on barges as anintegral part of the barge and to utilize the barge as a drilling baseduring the drilling of the borehole into the earths substrata in marinelocations. However, this method is relatively expensive, time consumingand very cumbersome to operate. Another method known in the art is toerect permanent foundations above the water and to position thereon thecomplete drilling rig which can be disassembled after the borehole hasbeen completed. Upon completion of the borehole, this particular type ofrig is disassembled, placed upon suitable marine transportation andtransported to a new location. The rig is then assembled in the newlocation. This method is very time consuming and also expensive.

In the art of drilling boreholes into the earths substrata, many marinedrilling operations are carried out at depths from about 20 to 100, to500 and greater feet below the surface of the water. Wells in thesemarine locations are dug or drilled to a depth of from 5,000 to 10,000feet and greater. In order to accomplish this, it is customary tofabricate and position a suitable marine foundation upon which the rigcan be erected for the handling of the drilling pipe necessary fordrilling the borehole and for conducting the various well completionoperations.

These permanent foundations upon which the rig is placed are constructedby various methods. One method, for example, is to drive concrete pilinginto the substrata of the lake or ocean bottom and thereafter to form aplatform 20 to 40 feet above the surface of the water. As pointed outabove, the derrick and other rig equipment are then positioned on theplatform for the drilling of the borehole and for the completion of thewell. These rigs vary greatly in weight as, for example, from about 150to 200 tons. Also wells may be drilled and completed at various ratesas, for example, one about every 20 to 40 days etc. Thus, after wellcompletion, there exists at the present time only two alternates,namely, to leave the rig intact on the foundation and to be dismantledat a later date, or to go through the expensive procedure ofdisassembling the rig, transporting it to a new location and thenreassembling the rig. If this latter procedure be followed on numerousoccasions, it is necessary to rework or clean out an existing Well.Thus, it is necessary to reassemble the rig for the reworking of theoriginal well and after completion of the reworking to again disassemblethe rig including the derrick.

In accordance with the present invention, a movable improved very stableplatform is utilized for such drilling operations, thereby effectinggreat time and many savings. The platform of the present invention maybe em- 3,104,531 Patented Sept. 24, 1963 "ice ployed in varying waterdepths and can be moved from location to location with reasonablefacility and minimum cost. This platform provides a sufficiently largeand stable area for drilling operations in varying depths of water.

' The mobile marine drilling foundation of the present inventioncomprises a unique system of submergible pontoons to provide therequired bearing on the bottom, a multiple legged columnar structureextending from the pontoons to above water level, and a working platformcarrying the derrick and related drilling machinery. Auxiliarymachinery, such as mud tanks and pumps, tubular goods storage, etc., maybe accommodated by a floating drilling tender or barge which will beanchored at one side of or near the Working platform.

The pontoons are arranged so that they will bridge any heterogeneousbottom condition and result in stable foundation. The support of thisfoundation results from bearing on the bottom or from a combination ofbuoyancy and bearing due to the displacement by the pontoons of softbottom soils; the relative amounts of each depend on the type of soilencountered and the buoyant force of the pontoons which can be adjustedthrough air chambers. Extending upwardly from the pontoons are columnarstructures or legs which are rigidly braced to the pontoon .system asrequired by the water depths in which the foundation is used.

The deck substructure or working platform is supported on these upwardlyextending legs at the varying heights required by the water depths. Thederrick and drilling floor in the preferred structure is cantileveredfar enough from the deck structure so that drilling can be done over theside of the foundation. This permits the foundation to be used inconjunction with a small permanent well head protection platform andwill allow workovers, such as the return of the foundation to the samelocation for reworking the well. It further permits, due to its-openside approach, the laying of gathering lines and power cables to thewell without danger of the pontoon system crushing or damaging suchinstallations.

The pontoon system, legs or columns, bracing, and platform may befabricated from any suitable materials such as concrete, steel,aluminum, and the like, or may be manufactured of any combinations ofthese materials, which may be best combined to achieve the desiredweights, structural strength, sizes, and resistance to corrosiveelements.

The mobile marine drilling foundation, comprising the pontoon system,columns, and working platform complete with derrick and machinery, willbe moved as a single unit from one location to the next. A crane barge(floating lifting device), after picking up the foundation and clampingit to the barge, may be towed by a tug to the next location to bedrilled. The pontoons preferably will remain submerged during this tow.Water may be removed from the pontoons by pumps or other suitableequipment to adjust the buoyancy and resultant weight to be lifted toreasonable limits.

A clamp is used to make the working platform fast to the columns at thevarying heights required. This device consists of a mechanicallyoperated clamp, pins, dogs, etc., which will safely transfer the loadsfrom the working platform to the columns. In addition to this clampingdevice, an adjusting mechanism is used to level up the derrick andprovide for any inclination of the foundation.

The present invention may be readily understood by reference to thedrawings illustrating embodiments of the same. FIG. 1 shows the mobileapparatus of the present invention positioned in a marine formation withthe derrick above the surface of the water. FIGS. 2, 3 and 4 illustratestructure details of the invention. FIGS.

S, 6 and 7 illustrate in some detail the mobile marine drillingfoundation lifting barge. FIG. 8 illustrates the lifting barge incombination with the mobile foundation and method of moving. FIG. 9illustrates the method of moving the mobile foundation by means of thelifting barge, while FIG. illustrates the method of positioning themobile foundation by means of the drilling barge on other barges formajor overhaul.

Referring specifically to FIG. 1, the equipment is shown positionedbeneath the surface of the water 1 on the bottom of the lake or groundbeneath the surface of the water. The apparatus comprises threeinter-related pontoons 2, 3 and 4 interconnected to one another in ahorizontal plane. Pontoons 2 and 4 are arranged with respect to eachother as a V with pontoon 3 intercepting these pontoons at approximatelytheir mid-point. Since it is preferred that pontoons 2, 3 and 4 besubstantially equal in length and diameter, pontoon 3 will over-extendpontoons 2 and 4, thereby greatly increasing the stability of thefoundation. In elfect, these three pontoons form an A frame with a crossconnecting member over-extending the other two members in order tosecure added stability.

Two vertically extending legs 6 and 7 extend upwardly from the crossconnecting pontoon 3 and are positioned on pontoon 3 between the pointswhere the V connected pontoons 2 and *4 intersect pontoon 3. A thirdvertically extending leg 8 is supported by braces 13 and 14, whichbraces extend angularly from pontoons 4 and 2, respectively.

A lower platform is supported above the surface of the Water by means ofthe vertically extending legs 6, 7 and 8. Brace 9 angularly extendinginwardly from pontoon 3 supports leg 6-, whereas brace 10 angula-rlyextending inwardly from pontoon 3 supports leg 7. Brace 11 extendingfrom pontoon 2, and brace 12 extending from pontoon 4, further supportleg 8. Horizontal braces 18, 19 and support upwardly extending legs 6, 7and 8 with respect to one another. The derrick floor 16 is positionedabove deck substructure 15 and supports derrick 17. The drilling floor16 over-extends substructure 15 and thus permits the drilling operationto be carried out in an off-center position, preferably, in the areadelineated by the cross member pontoon and the base of the V membersgenerally designated as lake or sea bottom 5. The upwardly extendinglegs are positioned preferably in equal distance one from the other.

It is to be understood that the drilling equipment such as drill pipe,handling equipment, motivating equipment, the method and means ofchanging the buoyancy of the pontoons, the method of equalizing thebuoyancy of the respective pontoons are not shown since these featuresare not part of the present invention. Furthermore, these features arewell known in the marine drilling art.

However, it is to be understood that the buoyancy of one pontoon may bevaried and different from the buoyancy of each of the other two. Thus,by varying the buoyancy of one pontoon with respect to the others,depending upon the nature of the subsoil, greater stability is secured.It is within the concept of the present invention to provide airchambers in each of the respective pontoons so as to have a differentbuoyancy as required at one end of the pontoon as compared with theother end of the pontoon, or one section of the individual pontoon ascompared to the buoyancy of another section. Thus, by way of example,areas A, B, C, D, E, F and G of the respective pontoons may each have adifferent buoyancy, depending upon the nature of the subsoil. As pointedout heretofore, the method and means for ejecting or admitting water andair to the respective areas is not illustrated since this does notconstitute a part of the present invention. Any satisfactory means, suchas air lines, check valves, pumping means, and the like, may beemployed. FIG. 2 is a plane view taken through A-'A. FIG. 3 is a frontview looking toward the overextending platform section, while FIG. 4 isa side view.,

Similar parts described in FIG. 1 are illustrated with similar numbersin FIGS. 2, 3 and 4. The well position with respect to the substructureis designated by 21 in FIG. 2.

While the precise measurements used for the various members will vary,depending upon the nature of the drilling operation to be carried outas, for example, the depth of the water, the size and weight of thederrick and auxiliary equipment and the diameter of the borehole to bedrilled as well as the depth and other drilling factors, onesatisfactory unit is one wherein the lengths of the pontoons areapproximately 210 feet. vary from about feet to about 400 feet andlonger. Under these conditions, pontoons 2 and 4 are V positioned sothat the height of the V is approximately 182 feet.

legs would approximate about feet below the water and about 30 feetabove the water, thus permitting the drilling platform to be positionedabove the surface of the water from about 0 feet to 30 feet. Thediameter of the pontoons may vary appreciably, but are generally in therange from about 10 to 20 feet. With respect to the particular apparatusillustrated, the diameter of the pontoons is approximately 12 feet.

Reference is made to FIGS. 5, 6 and 7, showing the general arrangementof the floating lifting device arrangement for removing the substructureand equipment from the mobile marine drilling foundation by means ofthefloating lifting device. FIG. 5 shows a top view of the floating liftingdevice, "FIG. 6 shows a side view, while FIG. 7 illustrates an end view.Similar parts in the respec.

mast 44. Hoist rigging 43 extending to winch 48 and 49 is illustrated inthe respective views. Power equipment to run the hoist and the barge isillustrated by 47.

Reference is made to FIG. -8 showing the general arrangemen-t forremoving the substructure and equipment from the mobile marine drillingfoundation by means of the floating lifting device. The upper and lowerplatform 15 and 16 by means of suitable equipment can be released fromlegs 6, 7 and 8 or locked on to these legs and the substructure of theequipment. Thus, in operation, the drilling platform comprising thederrick, the platform floors and the pontoon structure, can be moved asa single unit, or the derrick and platforms can be moved separately fromthe pontoon structure. The method of raising the platform floors 15 and16, or lowering said floors with respect to the legs 6, 7 and 8 is notshown. Suitable means wellknown in the art may be employed. In general,utilizing the two hoists 42 and 62 attached to booms 51 and 41,respectively, permits these hoists to be attached to separatesides ofthe equipment, thereby gaining much greater stability. Similar parts ofFIG; 8 with respect'to the previously described figures are designatedby similar numbers.

FIG. 9 illustrates a position of the mobile marine drilling foundationand the floating lifting device during transportation. It is to be notedthat in this method of operation the respective platforms supporting thederrick are located and locked on legs 6, 7 and 8, thus permitting thetransportation of the entire apparatus as an integral unit.

Similar parts of FIG. 9 illustrated in the preceding drawrangement ofthe mobile marine drilling foundationre moved from the Water by means ofthe floating lift The lengths may 1 device and readily placed uponfloating barges for the purposes of major maintenance and overhaul.Similar elements of FIG. previously described .in preceding drawings aresimilarly numbered. By way of example, in operation the procedural stepsfor moving the present foundation unit from a shallow water location toa deep water location comprises:

Using the lifting crane, the deck is raised to a height required for thedeep water locaiton. The deck is made fast to points atop the columnsfor the lifting and towing unit. Water is removed from the pontoons. Theunit is lifted clear of the lake bottom and clamped to the crane bargeand towed to a deep water location. The unit is freed from the barge andlowered to rest on the bottom by flooding the pontoons. The deckstructure is leveled on the columns as required by the sloping lakebottom.

Water is displaced partially from the pontoons to increase buoyancy.Positive buoyancy should never be achieved. The foundation unit is thenready for operation.

If the foundation unit is to be moved from a deep water location to ashallow water location, the following procedural steps are employed: Thehoists are made fast to lifting points atop the columns and water isremoved from the pontoons. The unit is lifted clear of the lake bottomand the column structure is clamped to the crane barge. The unit istowed to a shallow water location. The foundation unit is freed of thebarge and lowered to rest on the bottom and the pontoons are flooded.Using the lifting crane, the deck is lowered as required for the shallowwater location. The deck structure is leveled on the columns as requiredby the sloping lake bottom. The water is displaced from the pontoons toincrease the buoyancy but positive buoyancy should never be achieved.The foundation unit is now ready for operation.

The apparatus of the present invention has the following advantages:

It is a self-contained foundation unit for drilling which is readily andefiiciently transported by a floating lifting device from one locationto the next.

It comprises a self-contained foundation unit for drilling which islifted by a floating lifting device and may be towed with its pontoonstructure submerged from one location to the next. The unit comprises aself-contained foundation unit for drilling which is lifted by afloating lifting device (crane barge) and is clamped to the stern of thelifting barge and is towed with its pontoon structure submerged from onelocation to the next. The unit also comprises a self-containedfoundation unit for drilling which is lifted by a floating liftingdevice (crane barge) and is clamped to the stern of the lifting barge,and is towed with its pontoon structure submerged, thereby eliminatingthe use of special devices such as outrigger-s, auxiliary buoyancyunits, and similar methods of obtaining floating stability. Also thestability of the foundation unit during the lifting and moving is due tothe principles involved in the carrying mechanism, and therefore doesnot have to be incorporated into the design of the foundaunit proper.

The foundation is stable under all soil conditions due to the use of thebearing area provided by the pontoons plus the buoyancy achieved throughthe volume of the pontoons and the arrangement for varying buoyancythrough the air chambers. The use of the bearing area provided by thepontoons, plus the buoyancy achieved through the volume of the pontoonsand the arrangement for varying the buoyancy through the respective airchambers allows the foundation to be very stable under all soilconditions and allows a preloaded condition to be established to aminimum, which reduces the movement due to working.

The use of the bearing area provided by the pontoons plus the buoyancyachieved through the volume of the pontoons and the arrangement forvarying the buoyancy through air chambers allows the foundation to bestable under all soil conditions and allows a preloaded'condition to beestablished. It also permits the weight of the mobile foundation to beadjusted for optimum carrying conditions. Also the arrangements forvarying the buoyancy through air chambers allows a maximum unit weightto be established during the drilling operations while the foundationunit is on the bottom, and at the same time allows a minimum unit weightto be established during lifting and towing operations. This principleof separate weights for the various operations makes possible the use ofa lesser capacity and, therefore, a more eflicient carrying device.

The arrangement of the cantilevered deck and the open pontoons systemallows this foundation to be used not only for original drilling, butalso to be moved back in on the same location for subsequent Workoversand routine maintenance. Also the arrangement of the cantilevered deckand the open pontoon system mlows this foundation to be used inconnection with a permanent production platform and at the same timepermits. flow lines, power cables and similar utilities to be run to thewell site without suffering any damage in connection with repeatedrelocations of the foundation.

The triangular arrangement of the three pontoons, in the form of an A,results in an extremely stable foundation. The use of the lifting deviceto lift and vary the height of the working platform in accordance withwater depths, without the use of jacks, screws, mechanical racnets orsimilar devices which would have to be integral parts of the foundationor be applied from an outside force, is very efficient.

What is claimed is:

1. An improved foundation for conducting drilling op erations in amarine location which comprises a substantially horizontal basestructure of interconnected pontoons, a vertically extending network ofcolumns and braces secured to said pontoon base, and a substantiallyhorizontal working platform supported by said network; said basecomprising first and second elongated, submergible pontoons joined at asubstantial angle, and a third pontoon cross-connecting said first andsecond pontoons to form a substantially A shaped configuration, withsaid third pontoon extending beyond each of its respective intersectionswith said first and second pontoons to secure added stability; saidvertically extending network comprising first and second verticallydisposed columnar members secured to said third pontoon between saidfirst and second pontoons, and a third vertically disposed columnarmember extending above the triangular area enclosed by said pontoons andsupported by braces interconnecting said first and second pontoonstherewith; said working platform comprising a cantilevered derrick floorextending horizontally above the area which lies between said first andsecond pontoons, but outside said enclosed triangular area.

2. An improved foundation for conducting drilling operations in a marinelocation which comprises a working platform adapted to have positionedthereon a derrick and auxiliary equipment, a base of threeinterconnected pontoons arranged in a horizontal plane to form anA-shaped structure with a cross-pontoon over-extending each of two otherpontoons, means to vary the buoyancy of said pontoons individually, anda vertically extending structure securely attached to said pontoons,towhich is attached said working platform; said vertically extendingstructure comprising three vertically extending legs which support saidworking platform, two of said vertically extending legs being attachedto said cross-pontoon between 'the two intersections of saidcross-pontoon with the other two pontoons, the third leg being dispose-dvertically above the triangular area enclosed by the intersecting threepontoons, said third leg being supported by brace members extendingang-ularly therefrom and attached to said two other pontoons; saidworking platform comprising a cantilevered derrick floor extendinghorizontally above the area partially enclosed by said cross-ponteon andthe diverging end portions of said two other ontoons, whereby the centerof said derrick floor lies vertically above said partially enclosedarea.

References Cited in the file of this patent UNITED STATES PATENTS Re.24,254 Dawson Dec. 11, 1956 Re. 24,346 Dawson Aug. 20, 1957 801,603Neale Oct. 10, 1905 2,210,408 Henry Aug. 6, 1941) OTHER REFERENCESConstruction Methods and Equip. pp". 94 and 95, Aug. 1950. EngineeringNews Record, Oct. 20, 1955, page 81.

1. AN IMPROVED FOUNDATION FOR CONDUCTING DRILLING OPERATIONS IN A MARINELOCATION WHICH COMPRISES A SUBSTANTIALLY HORIZONTAL BASE STRUCTURE OFINTERCONNECTED PONTOONS, A VERTICALLY EXTENDING NETWORK OF COLUMNS ANDBRACES SECURED TO SAID PONTOON BASE, AND A SUBSTANTIALLY HORIZONTALWORKING PLATFORM SUPPORTED BY SAID NETWORK; SAID BASE COMPRISING FIRSTAND SECOND ELONGATED, SUBMERGIBLE PONTOONS JOINED AT A SUBSTANTIALANGLE, AND A THIRD PONTOON CROSS-CONNECTING SAID FIRST AND SECONDPONTOONS TO FORM A SUBSTANTIALLY A-SHAPED CONFIGURATION, WITH SAID THIRDPONTOON EXTENDING BEYOND EACH OF ITS RESPECTIVE INTERSECTIONS WITH SAIDFIRST AND SECOND PONTOONS TO SECURE ADDED STABILITY; SAID VERTICALLYEXTENDING NETWORK COMPRISING FIRST AND SECOND VERTICALLY DISPOSEDCOLUMNAR MEMBERS SECURED TO SAID THIRD PONTOON BETWEEN SAID FIRST ANDSECOND PONTOONS, AND A THIRD VERTICALLY DISPOSED COLUMNAR MEMBEREXTENDING ABOVE THE TRIANGULAR AREA ENCLOSED BY SAID PONTOONS ANDSUPPORTED BY BRACES INTERCONNECTING SAID FIRST AND SECOND PONTOONSTHEREWITH; SAID WORKING PLATFORM COMPRISING A CANTILEVERED DERRICK FLOOREXTENDING HORIZONTALLY ABOVE THE AREA WHICH LIES BETWEEN SAID FIRST ANDSECOND PONTOONS, BUT OUTSIDE SAID ENCLOSED TRIANGULAR AREA.